I am using the following function to plot columns from a CSV-file: plot_mi_time = function(mdata, miname) { mdata2 = mdata[row.names(mir_test) == miname, ] # print(mdata2) plot(c(1:3), mdata2, xaxt="n", ylab="Expression", xlab="Time(h)", , main=miname, pch=16) axis(1, at=c(1,2,3),labels=c("a","b","c")) } No I have a CSV file with 2 replicate columns that belongs to the same column-name. Any suggestions how I can edit that formula to plot 2 y-values for the same x-value? -- View this message in context: http://r.789695.n4.nabble.com/Plot-duplicate-csv-columns-tp3562708p3562708.html Sent from the R help mailing list archive at Nabble.com.